1. Field
The present disclosure generally relates to detection of presence, or absence, and identification of objects tagged with transponders, which may, for example, allow detection and identification of surgical objects (e.g., sponges, instruments, etc.) during or after surgery, or for inventorying of objects, for instance surgical objects.
2. Description of the Related Art
It is often useful or important to be able to determine the presence or absence of an object.
For example, it is important to determine whether objects associated with surgery are present in a patient's body before completion of the surgery. Such objects may take a variety of forms. For example, the objects may take the form of instruments, for instance scalpels, scissors, forceps, hemostats, and/or clamps. Also for example, the objects may take the form of related accessories and/or disposable objects, for instance surgical sponges, gauzes, and/or pads. Failure to locate an object before closing the patient may require additional surgery, and in some instances may have serious adverse medical consequences.
Some hospitals have instituted procedures which include checklists or require multiple counts to be performed to track the use and return of objects during surgery. Such manual approaches are inefficient, requiring the time of highly trained personnel, and are prone to error.
Another approach employs transponders and a wireless interrogation and detection system. Such an approach employs wireless transponders which are attached to various objects used during surgery. The interrogation and detection system includes a transmitter that emits pulsed wideband wireless signals (e.g., radio or microwave frequency) and a detector for detecting wireless signals returned by the transponders in response to the emitted pulsed wideband signals. Such an automated system may advantageously increase accuracy while reducing the amount of time required of highly trained and highly compensated personnel. Examples of such an approach are discussed in U.S. Pat. No. 6,026,818, issued Feb. 22, 2000, and U.S. Patent Publication No. US 2004/0250819, published Dec. 16, 2004.
However, some of these approaches do not allow identification of the object. Conventional approaches that allow identification of the object via transmitting an identifier typically transmit a signal at frequencies that have a short range of detection, which may inhibit detection of the transponder, and thus, the object attached thereto. Furthermore, these transponders may not be detectable by the interrogation device when they are situated such that there is an obstacle or membrane, such skin or flesh, between the transponder and the interrogation device.
Consequently, a new approach to uniquely identify and detect presence and absence of a transponder assembly as well as identification is desirable.